Fuel-injection system for internalcombustion engines



June 18, 1957 c. M. PERKINS 2,795,058

FUEL-INJECTION SYSTEM FOR INTERNAL-COMBUSTION ENGINES Filed Aug. 23, 1956 IN V EN TOR. CHARLES M. PERKINS A TORNEY 7 2,796,058 Ice Patented June 18, 1957 FUEL-INJECTION SYSTEM FOR INTERNAL- COMBUSTION ENGINES Charles M. Perkins, Philadelphia, Pa.

Application August 23, 1956, Serial No. 605,814

2 Claims. (Cl. 123-439) The particular embodiment of the present invention,

which is illustrated in the drawings and which will be described hereinafter in greater detail, comprises gen-.

erally an auxiliary cylinder connected to fiuid communication with the head end of a combustion cylinder, an auxiliary piston movable in the auxiliary cylinder and normally urged toward the connected end of the latter, so that a compression stroke of a working piston in the combustion cylinder forces air or other combustion supporting fluid from the combustion cylinder into the auxiliary cylinder and moves the auxiliary piston away from the connected end of the auxiliary cylinder. On the expansion stroke of the working piston the fluid from the auxiliary cylinder returns to the combustion cylinder. A fuel injector is located in the connection between the combustion and the auxiliary cylinders, and a plunger is movable in the fuel injector in response to movement of the auxiliary piston for injecting fuel during the expansion stroke of the working piston into the combustion cylinder along with and in a desired proportion with respect to the combustion supporting fluid returned to the combustion cylinder.

As is Well known to those versed in the art, intern-a1 combustion engines, and particularly those working on the diesel cycle, are subject to numerous difliculties, such as the proper control of fuel-air ratio, and insuring complete and ethcient combustion of fuel at desired combustion pressures. Further objections to prior diesel engines of practical construction are the necessity for using relatively high cost fuel, and the inability of injection systems to accurately compensate for density of intake air, say as alfected by change in operating altitude. An additional disadvantage is the incapability of prior engines to efficiently operate in opposite directions of crankshaft rotation without complicated timing changes in fuel injection.

It is, therefore, an object of the present invention to provide an improved internal combustion engine construction and fuel injection system therefor, which overcomes the above mentioned difficulties, positively controls the air-fuel ratio and combustion pressure, andinsures complete and efficient fuel combustion at desired pressure.

It is a corollary object of the present invention to provide a fuel injection system having the advantageous characteristics mentioned in the foregoing paragraph, which automatically and inherently compensates for change in density of air employed in combustion, to insure complete and eflicient combustion and proper fuel-air ratio at all operating elevations.

It is another object of the present invention to provide an internal combustion engine fuel injection system of the type described which is capable of highly satisfactory performance and economical operation when employing relatively inexpensive and heavy oils, such as bunker C.

It is another important object of the present invention to provide a fuel injection system for an internal combustion engine which enables the engine to be selectively operated in either direction, without requiring adjustment of cams, or other timing means, but only starting of the engine in the desired direction.

It is a further object of the present invention to provide a fuel injection system for an internal combustion engine which is simple and durable in construction, reliable in use, and which can be manufactured, operated and maintained at reasonable cost.

Other objects of the present invention will become apparent upon reading the following specification and referring to the accompanying drawings, which form a ma terial part of this disclosure.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts, which will be exemplified in the construction hereinafter described, and of which the scope will be indicated by the appended claims.

In the drawings:

Figure l is a sectional elevational view, partly broken away, showing a fuel injection device of the present invention in operative association with the combustion cylinder of an internal combustion engine;

Figure 2 is a sectional view taken substantially along the line 22 of Figure 1;

Figure 3 is a sectional view taken substantially along the line 33 of Figure 1; and

Figure 4 is a sectional view taken substantially along the line 4 4 of Figure l.

Referring now more particularly to the drawings, and specifically to Figure 1 thereof, 10 designates generally the upper portion of an internal combustion engine cylinder, and 11 deisgnates a working piston movable vertically in the cylinder. An auxiliary chamber or cylinder 12 is arranged over and adjacent to the upper or head end of the combustion cylinder 10, and is provided interiorly thereof with an auxiliary piston 13.

The combustion cylinder 10 includes a generally cylindrical side wall 15 and a top wall or head 16 formed with a central upwardly flaring opening or hole 17 and a pair of valve ports 18 and 19. Arranged in the ports 18 and 19 are valves 20 and 21, which are movable for opening and closing their respective ports, and, operatively connected to any suitable actuating means (not shown) such as a cam shaft, for operation in properly timed relation.

The working piston 11 is vertically shiftable in the corn bustion cylinder side wall 15 for movement toward and away from the combustion cylinder head 16, and may include a piston rod 24 and piston rings 25. Centrally of the upper or head end of the piston 11 is preferably formed a recess 26 facing toward and in substantial registry with the central cylinder head opening 17.

The auxiliary cylinder 12 is preferably arranged over and in substantial alignment with the combustion cylinder 10, and includes a generally cylinder side wall 29, and an upper end or top wall 30 extending across and closing the upper end of the side wall. Extending inwards from the lower end of the auxiliary cylinder side wall 29, spaced above the combustion cylinder head 16, is a generally annular auxiliary cylinder bottom wall 31 which defines a central opening 32 in substantial alignment with thecylinder head opening 17. Depending from the inner edge of the annular auxiliary cylinder bottom wall 31 and into areaozse the cylinder head opening 17, is a generally cylinder connecting memberor tube 35. The tubular member 35 is formed about its exterior with a generally conical, downwardly tapering shoulder 36 received in the combustion cylinder head opening 17 and preferably seated therein on a generally conical gasket ring 37. Depending from the lower end of the tube 35 into the combustion cylinder 10, and spacedly received in the recess 26 of the piston 11 when the latter is in its illustrateduppermost position, is a downwardly dished spider 41) having a plurality of radial legs 41 extending generally upwards and outwards for connecton to the tube 35, and defining in the interleg spaces a plurality of circumferentially arrangedopenings 42.

In order to releasably lock the auxiliary cylinder 12 in its operative assembly with the combustion cylinder 10, with the tube shoulder 36 seated in sealing engagement on the gasket 37, a plurality of holding members orbars 45 are arranged about the tube 35 in bearing engagement with the upwardly facing surface of the shoulder 36 and secured to the combustion cylinder top wall 16 by screws or fasteners 46 extending into the latter top wall. Thus, the fasteners 4 draw the bars 45. downwardly against the shoulder 36 to effectively wedge the latter into the cylinder head opening 17.

It will now be appreciated that the auxiliary cylinder 12 has its lower internal end region connected, through the tube 35 in fluid communication with the upper internal or head end region of the combustion cylinder 10. That is, the internal region of the auxiliary cylinder 12 below the piston 13 is connected by the tube 35 in fluid communication with the upper internal region of the combustion cylinder 10 above the piston 11.

The auxiliary piston 13 may be of generally cylindrical configuration, and freely movable vertically in the auxiliary cylinder. That is, the auxiliary piston is not mechanically constrained. Upper and lower piston rings 49 and 50 are circumposed about the auxiliary piston 13 for sliding and sealing engagement with the interior of the auxiliary cylinder side wall 29; and, the auxiliary piston is formed with a circumferential, annular outwardly opening groove or recess 51 spaced between the upper and lower auxiliary piston rings. An annular retaining member 52, which may be generally T-shaped in section, is fixedly secured internally of the auxiliary cylinder side wall 29, so as to be received within the auxiliary piston recess or groove 51, and supports or holds a pair of upper and lower annular cushions or bumpers 53 and 54 within the auxiliary piston groove 51. As seen in Figure 1, the upper cushion 53 is engageable with the upper side of auxiliary piston groove 51 to limit downward movement of the auxiliary piston; and, the lower cushion 4 is engageable with the lower side wall of the auxiliary piston groove to limit upward movement of the auxiliary piston.

Centrally of the auxiliary piston 13 is formed a generally circular cavity or recess 57 which opens downwards into and substantially concentric with the tube 35. A rod-like extension or plunger 58, preferably formed integral with the auxiliary piston 13, depends from the upper or inner end wall of the auxiliary piston cavity 57 spacedly within the latter, and extends downwards beyond and out of the cavity.

Fixedly secured in concentrically spaced relation within the connection tube 35 and auxiliary piston cavity 57 is a fuel injector, generally designated 60. The injector includes a generally cylindrical body 61 fixedly secured in position by a plurality of radial struts or supports 62 extending from the injector body to the connector tube 35 in the space there between. The injector body 61 is formed in its lower region with a generally cylindrical internal hollow 63, which opens upwards through a generally cylindrical, concentric bore 64 for slidably re.- ceiving the auxiliary piston extension or plunger 58. That is, the bore 64 opens at its lower end into the internal hollow 63 and opens upwards through the injector body 61 for slidably receiving the depending plunger 58,

For simplicity of terminology, the injector hollow 63 and bore 64 may be considered as an internal chamber formed in the injector body 61.

The lower end wall or discharge head 65 of the injector body 61 is formed with a generally vertically disposed, concentric bore 66 opening downwards toward the dished spider 40 of the connection tube 35, and opening upwards into the lower injector chamber portion 63. An internal shoulder or reduced portion 67 is formed adjacent to the 70 on the upper end of the injector body. The generally annular recess 69 opens into the upper end of a generally vertically disposed passageway 72 which extends downwards within the injector body 61 eccentrically thereof, and terminates short of the lower enlarged chamber portion 63. Thus, the injector body passageway 72, which communicates at its upper end through the recess 69 to the plunger 58, is entirely separate from the injector chamber defined by the lower hollow 63 and bore 64, and closed to the chamber by the. plunger 58. A sealing gasket or wiper ring 75 is fixedly secured within the upper region of the injector body recess 69, surrounding and in snug engagement with the plunger 58. That is, the wiper 75 is fixedly secured to the side wall 70 of the recess 69, spaced above the bottom wall of the latter, and slidably engages the plunger to close the recess, except for its communication with the passageway 72.

Fixedly secured generally horizontally within the lower hollow 63 of the injector chamber is a perforate guide member or plate 77, which is formed with a central hole or aperture 78 in substantial alignment with the bore 66 of the lower injector body end Wall 65. A vertically shiftable plug 80 is slidably mounted in the holes 66 and 78 for opening and closing the discharge passageway 68, and resiliently urged toward its position of movement closing the discharge passageways. More particularly, the plug 80 includes an enlarged upper end portion or head 81 vertically slidable in the central openings 78 of the guide plate 77, and an enlarged lower end, portion or head 82 vertically slidable in the bore 66 below the shoulder 67. In the drawings, the plug 80 is in its uppermost position, with. the enlarged lower end portion 82 abutting against the underside of the shoulder 67 and closing the discharge passageway 68, while downward movement of the plug will enable the discharge passageway to communicate between the interior of the chamber 63 and exterior of the injector body. A helical compression spring 83 is circumposed about the plug 80. and has its opposite ends bearing against the enlarged upper plug end 81 and shoulder 67 to resiliently urge the plug upwards toward its position of movement closing the discharge passageway 68.

The interior of the chamber 63 is connected in one-way fluid communication with a source of liquid fuel supply (not shown), as by a conduit 85, and a one-way check valve 86. Further, a conduit 87 connects the lower end of the passageway 72 for fluid communication with the supply conduit 85, at some point between the check valve 86 and fuel supply. An additional conduit 89 is connected to the auxiliary cylinder top wall 30 for fluid communication between the upper interior region of the auxiliary cylinder 12, above the piston 13, and a source of fluid under substantially constant, relatively high pressure.

Of course, it is understood that the structure described hereinbefore is preferably duplicated with each cylinder of aninternal combustion engine, and, that the following description of operation is applicable to all cylinders of the engine.

The valves 20 and 21 are, each operated during one stroke of the engine cycle for respectively admitting air and discharging the products of combustion. For two strokes of the operating cycle, namely the compression and expansion strokes, the valves 20 and 21 are closed. During the compression stroke, air in the cylinder is compressed and forced upwards through the spider 40,

and tube 35 into the lower end region of the auxiliary cylinder 12. The upper end region of the auxiliary cylinder is provided with a relatively high pressure fluid, so that the auxiliary piston 13 yieldably resists upward movement away from the bottom wall 31 of the auxiliary cylinder. However, this resistance to upward movement of the piston 13 is overcome upon continued upward movement of the working cylinder 11 on its compression stroke, until the auxiliary piston 13 has been elevated or moved to its extreme upward position against the resilient, yieldable force of high pressure fluid within the upper region of the auxiliary cylinder. The compression stroke of the working cylinder 11 thus serves to force compressed air from the combustion cylinder into the auxiliary cylinder and effect upward movement of the auxiliary piston.

As the auxiliary piston 13 is moved upwards against its yieldable resisting force during the compression stroke of the working piston, the auxiliary piston extension or plunger 58 is simultaneously moved upwards in the upper injector chamber portion or bore 64 to increase the size of the injector chamber. Stated otherwise, upward movement of plunger 58 in the bore 64 reduces the pressure within the injector chamber, and thus serves to draw fuel through the one-way valve 86 and conduit 85 into the interior chamber of the injector body. It will now be understood that a quantity of fuel is drawn into the injector body 61 in proportion to the quantity of air compressed by the working cylinder 11 and forced into the auxiliary cylinder 12. That is, the quantity of compressed air forced into the auxiliary cylinder determines the amount of vertical movement of the auxiliary piston 13, which in turn determines the amount of vertical movement of plunger 58, and hence the quantity of fuel drawn into the injector body.

On the expansion stroke of working piston 11, the latter piston moves downwards away from the cylinder head 16, thus reducing the pressure in the cylinder 10, and consequently, through the tube 35, effecting reduction of the pressure in the lower region of auxiliary cylinder 12. When the pressure in the lower region of auxiliary cylinder 12 is reduced below that in the upper region of the auxiliary cylinder, the auxiliary piston 13 will move down. Viewed otherwise, downward movement of the working piston 11 on its expansion stroke draws air into the cylinder 10 from the lower region of the auxiliary cylinder 12, to enable the auxiliary piston 13 to move downwards.

Simultaneously with the movement of air from the auxiliary cylinder through the tube 35 and spider openings 42 into the cylinder 10, the plunger 58 moves downwards in the injector chamber to increase the pressure of the contained liquid fuel. This increased fuel pressure within the injector chamber serves to move the plug 80 downwards against the force of spring 83, and thereby open the passageway 68 of the discharge head 65 for discharging fuel outwards from the injector towards the spider openings 42. Thus, the end wall or discharge head 65 combines with the plug 80 to define an injector discharge nozzle.

Any fuel leaking through the bore 64 to the recess 69, including that carried by the plunger 58 and wiped therefrom by the wiper 75, will be recovered by movement through the passageway 72 back to the fuel supply conduit.

It will now be appreciated that the fuel is injected into the cylinder 10 along with movement of the combustion supporting air into the latter cylinder, and also, that the quantity of injected fuel is always proportional to that of air for combustion, and may by correct design be properly and accurately proportioned. Moreover, injection of the fuel is substantially continuous, occurring throughout the period of combustion, to insure the complete and efficient burning of the fuel, as well as to promote relatively constant combustion pressure. More specifically, any uneven combustion causing sharp increase or decrease in pressure will serve to decrease or increase the rate of fuel injection, respectively, and thereby insure relatively even combustion pressure.

It will also be noted that the timing of fuel injection is controlled entirely by movement of the particular working piston, so that the direction of crankshaft rotation in effecting piston movement is inmaterial as regards compression, combustion and expansion, and the engine is therefore capable of operation in opposite directions.

From the'foregoing, it is seen that the present invention provides a fuel injection system for an internal combustion which fully accomplishes the intended objects, and is well adapted to meet practical conditions of manufacture and use. A

Although the present invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it is understood that certain changes and modifications may be made within the spirit of the invention and scope of the appended claims.

What is claimed is:

1. In an internal combustion engine including a combustion cylinder, and a working piston movable in the combustion cylinder, an auxiliary cylinder having one end connected in fluid communication with the head end of said combustion cylinder, a freely movable auxiliary piston in said auxiliary cylinder, the other end of said auxiliary cylinder being adapted for connection in fluid communication with a source of relatively high pressure fluid for yieldably urging said auxiliary piston toward said one auxiliary cylinder end, the compression stroke of said working piston serving to force fluid from said combustion cylinder into said one auxiliary cylinder end and effect movement of said auxiliary piston away from said one auxiliary cylinder end, and the expansion stroke of said working piston serving to return the fluid from said one auxiliary cylinder end to said combustion cylinder and effect movement of said auxiliary piston toward said one auxiliary cylinder end, a fuel injector located in the connection between said combustion and auxiliary cylinders and having an internal chamber adapted for connection in one way fluid communication with a source of fuel supply for receiving fuel from said source, a nozzle on said injector for discharging fluid from said chamber to said combustion cylinder and operable in response to increased fuel pressure in said chamber, and a plunger movable in said injector chamber and connected to said auxiliary piston for movement with the latter to draw fuel into said chamber upon said compression stroke and increase the fuel pressure in said chamber upon said expansion stroke, whereby said nozzle is operated upon said expansion stroke and fuel is injected during said expansion stroke into said combustion cylinder along with and in proportion to the fluid returning to said combustion cylinder, said injector being formed with a fuel recovery passageway separate from said chamber and opening at one end to said plunger, the other end of said fuel recovery passageway being :adapted for connection to said source of fuel supply, and a wiper fixed in said fuel recovery passageway and engageable with said plunger to wipe fuel from the latter into said fuel recovery passageway, whereby fuel wiped from said plunger is adapted to be returned to said source of fuel supply.

2. A fuel injector system for an internal combustion engine including a combustion cylinder and a working piston movable in the combustion cylinder, said system comprising an auxiliary cylinder having one end connected in fluid communication with the head end of said combustion cylinder, an auxiliary piston movable in said auxiliary cylinder and biased at a substantially constant '7 o c t ar aid, one au i ary cy der end, th com: pression stroke of said working piston serving to force fluid from said combustion cylinder into saidone auxiliary cylinder end and effect movement of said auxiliary piston away from said one auxiliary cylinder end, and the expansion stroke of said working piston serving to return the fluid from said one auxiliary cylinder end to said combustion cylinder and effect movement of said auxiliary piston toward said one auxiliary cylinder end, a, fuel in,- jector located in spaced relation in the connection between said combustion and auxiliary cylinders and having an internal chamber adapted to receive fuel from a source of fuel supply, a check valve connected to said injector for permitting the flow of fuel into and preventing the flow of fuel out of said injector chamber, a nozzle on said injector for discharging fuel from said chamber to said combustion cylinder and operative in response to increased fuel pressure in said chamber, and a plunger movable in said injector chamber-and connected to said auxiliary piston for movement with the latter to draw 20 fuel into said chamber upon said compression stroke and in re s the u p sure n sai ch mber p n i c.

pansicmstrqke, wher by said. no z Operative p n.

said expansion stroke and fuel is injected during said expansion stroke into said combustion cylinder along with and in proportion to the fluid returned to said combustion, cylinder, said injector being formed with an, internal fuel recovery passageway separate from said chamber and having one, end portion extending about and opening toward said. plunger, the other end of said fuel recovery passageway being adapted for connection to said source of fuel supply, and a wiper fixed in said one end portion of said fuel recovery passageway and extending about and in engagement with said plunger to wipe fuel from the latter into said passageway upon movement of said plunger, where-by fuel wiped from said plunger is adapted to bereturnedto said source of fuel supply.

References Cited in the file of this patent UNITED STATES- PATENTS 2,204,570 Butler June 18, 1940 FOREIGN PATENTS 825,318 France Dec. 8, 1937 

